KR101282038B1 - Air conditioner and method of controlling the same - Google Patents

Abstract

The present invention can increase the accuracy and precision of the refrigerant amount detection and refrigerant leakage by determining whether the refrigerant leaks after detecting the refrigerant amount in accordance with the pressure and room temperature of the compressor during the refrigerant amount detection mode.

The present invention is an outdoor unit; A compressor provided to the outdoor unit; And a controller provided in the outdoor unit to detect the amount of refrigerant circulated by driving the compressor at a constant operation rate and determine whether the refrigerant is leaked according to the detected amount of refrigerant.

Description

Multi air conditioner and its control method {Air conditioner and method of controlling the same}

The present invention relates to a multi-air conditioner and a control method thereof, and more particularly, to a multi-air conditioner and a control method for checking the leakage of the refrigerant using the existing pressure detection unit and the temperature detection unit.

An air conditioner is a device that is arranged in a room, a living room, an office, a business store, and the like to maintain a comfortable indoor environment by controlling air temperature, humidity, cleanliness, and airflow.

There is a multi-type air conditioner provided with indoor units in a plurality of spaces for cooling or heating a plurality of indoor spaces of the air conditioners.

The multi-type air conditioner includes a compressor for compressing a refrigerant at a high temperature and high pressure, an accumulator for separating liquid refrigerant from the refrigerant flowing into the compressor, an outdoor heat exchanger connected to allow the refrigerant to flow through the discharge port of the compressor, A plurality of indoor heat exchangers are provided in the indoor space.

The air conditioner is connected to each component is provided with a refrigerant pipe for circulating the refrigerant between the outdoor heat exchanger and the plurality of indoor heat exchangers.

In particular, an air conditioner having a plurality of indoor units is used because the length of the refrigerant pipe is very long, using a long pipe or connecting a refrigerant pipe of a suitable length using a method such as welding.

When the refrigerant pipe is connected by a long pipe or welding, such as, if the welding of the refrigerant pipe is not properly performed or sufficient management is performed, the welded part may be broken, and the refrigerant may leak through the broken part.

If the leakage of refrigerant occurs through the damaged part, the heat exchange efficiency as much as desired cannot be obtained. Therefore, after checking the refrigerant leakage for each refrigerant pipe, supply the insufficient amount of refrigerant to ensure a smooth heat exchange cycle. do.

However, if a refrigerant leak occurs during the operation of the air conditioner, it is difficult to find it as soon as possible, and it is possible to accurately measure the amount of refrigerant remaining in the current air conditioner even after the refrigerant leak is confirmed due to a considerable amount of refrigerant leakage. As a result, re-vacuum and re-injection operations have to be carried out after the recovery of the entire refrigerant, which is a costly and time-consuming and severely adverse effect on the global environment.

Since the conventional technique for reading the amount of refrigerant uses a method of determining the leakage state of the refrigerant using data measured during normal operation of the air conditioner, it is difficult to read the change of refrigerant injection amount due to the minute leakage of the refrigerant, The accuracy and precision are also much lower.

In addition, since a separate inspection device or component is used to check the leakage of the refrigerant, there is a problem of an increase in cost and a complicated manufacturing process.

Accordingly, the present invention has been made to solve the above problems, an object of the present invention is to perform a refrigerant amount detection mode for detecting the amount of refrigerant to detect the amount of refrigerant and then determine whether the refrigerant leaks, The present invention provides a multi-air conditioner with improved precision and a control method thereof.

In addition, another object of the present invention is to provide a multi-air conditioner and a method of controlling the same according to the application model and the installation conditions, since it is determined whether the refrigerant leakage according to the amount of refrigerant detected according to the outdoor temperature after performing the refrigerant amount detection mode.

In addition, another object of the present invention is to provide a multi-air conditioner and a control method for determining whether the refrigerant is leaked after detecting the amount of refrigerant simply and easily using the existing pressure detector and the temperature detector after performing the refrigerant amount detection mode. To provide.

Technical means of the present invention for achieving the above object is an outdoor unit; A compressor provided in the outdoor unit; And a controller provided in the outdoor unit to detect the amount of refrigerant circulated by driving the compressor at a constant operation rate and determine whether the refrigerant is leaked according to the detected amount of refrigerant.

The apparatus may further include a first pressure detector configured to detect the inlet pressure of the compressor, a second pressure detector configured to detect the outlet pressure, and a first temperature detector configured to detect the heat exchanger outlet temperature of the outdoor unit, and the controller may correspond to the compressor outlet pressure. The degree of subcooling according to the difference between the saturation temperature and the heat exchanger outlet temperature of the outdoor unit is calculated, and the amount of refrigerant is detected through the subcooling and the inlet and outlet pressures of the compressor.

In addition, the control unit rotates the outdoor unit fan at a rotational speed corresponding to the temperature sensed by the first temperature sensor at a time when the compressor starts to operate at a constant operation rate so that the discharge pressure of the compressor is kept constant.

The apparatus may further include a plurality of indoor units connected to the outdoor unit, and the controller may drive the compressor for a predetermined time even if the control temperature of each indoor unit is lower than the target temperature.

The apparatus may further include a second temperature detector configured to detect an inlet temperature of the heat exchanger of each indoor unit, and a third temperature detector configured to detect an outlet temperature of the indoor unit, and the controller may control the superheat degree according to the temperature difference between the inlet temperature and the outlet temperature of the heat exchanger of the indoor unit. After the calculation, the opening degree of the indoor electromagnetic expansion valve provided in the indoor unit is controlled to maintain the calculated superheat at a constant temperature.

In addition, when there are a plurality of outdoor units, the controller further includes a central control unit for determining whether the refrigerant is leaked according to the amount of refrigerant transmitted from the control unit provided in each of the plurality of outdoor units.

The technical method of the present invention for achieving the above object is a process for detecting the amount of refrigerant circulated by driving the compressor provided in the outdoor unit at a constant operating rate when operating in the refrigerant amount detection mode, and determining whether the refrigerant leaked according to the detected amount of refrigerant Do this.

In addition, when operating in the refrigerant amount detection mode, the temperature of the outdoor heat exchanger outlet provided in the outdoor unit is sensed, and the fan of the outdoor unit rotates at a rotational speed corresponding to the temperature of the outdoor heat exchanger outlet detected at the time of starting operation in the refrigerant amount detection mode. To control the speed.

When the amount of refrigerant is detected, the pressure of the inlet and outlet of the compressor is sensed, the supercooling degree is calculated according to the difference between the saturation temperature according to the pressure of the outlet of the compressor and the initial detection temperature of the outlet of the outdoor heat exchanger of the outdoor unit. The amount of refrigerant is detected through the pressure of the discharge port.

In addition, when operating in the refrigerant amount detection mode, even if the control temperature of the plurality of indoor units connected to the outdoor unit is lower than the target temperature, the operation of the compressor is maintained for a predetermined time, and after detecting the inlet and outlet temperatures of the indoor heat exchanger provided in the indoor unit, The superheat degree is calculated according to the temperature difference between the inlet and the outlet, and the opening degree of the indoor electromagnetic expansion valve provided in the indoor unit is controlled to maintain the superheat degree at a constant temperature.

When there are a plurality of outdoor units, the average refrigerant amount of the detected refrigerant amounts of the plurality of outdoor units is calculated, and it is determined whether the refrigerant leaks according to the average refrigerant amount.

As described above, according to the present invention, after the refrigerant amount is detected according to the pressure and the outdoor temperature of the compressor after operating in the refrigerant amount detection mode, the refrigerant amount is detected and whether the leakage of the refrigerant increases the accuracy and accuracy of the refrigerant amount. Can be.

In addition, by performing the refrigerant amount detection mode, it is possible to detect the amount of refrigerant using the existing pressure sensing unit and the temperature sensing unit without using a separate inspection device or parts, and to determine whether the refrigerant leaks according to the refrigerant amount detection to prevent cost increase. It is possible to simplify the manufacturing process and to determine whether the refrigerant leaks easily and easily.

In addition, since the amount of refrigerant is detected by applying a model-specific specification, the amount of refrigerant corresponding to various outdoor temperature conditions can be detected, thereby reducing the deviation of temperature, installation conditions, and models.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of a multi-air conditioner according to an embodiment, in which a plurality of indoor units are connected to one outdoor unit.

The outdoor unit 1 includes a compressor 11, an outdoor heat exchanger 12, an outdoor fan 13, an accumulator 14, a main electromagnetic expansion valve 16, a first temperature sensing unit T1, and first and second pressures. Comprising a sensing unit (PH, PL), a plurality of indoor units (2) are arranged in parallel, each indoor unit (2) is an indoor heat exchanger (15), an indoor electromagnetic expansion valve (17), second, third temperature sensing unit It consists of (T2, T3). This configuration will be described in detail.

The compressor 11 is provided in the outdoor unit and compresses the gaseous refrigerant injected from the accumulator to a state of high temperature and high pressure and discharges it to the outdoor heat exchanger.

The compressor 11 is composed of at least one, and when a plurality of compressors are configured, only one of the compressors may be driven at a constant operation rate of 100% or the plurality of compressors may be operated at a predetermined ratio for a predetermined time. .

The refrigerant pipe connecting the intake port of the compressor 11 among the refrigerant pipes is a low pressure pipe for guiding the flow of the expanded low pressure refrigerant, and the first pressure detection unit PL of the plurality of pressure detection units is an intake port of the compressor 11. It is provided in the low pressure pipe to detect the pressure of the low pressure pipe of the compressor and transmits the detected pressure to the control unit.

The refrigerant pipe connected to the discharge port of the compressor 11 among the refrigerant pipes is a high pressure pipe for guiding the flow of the high pressure refrigerant discharged from the compressor 11, and the first pressure sensing unit PH is a high pressure pipe that is the discharge port of the compressor 11. Provided in the sensing pressure of the high pressure tube of the compressor and transmits the detected pressure to the control unit.

The outdoor heat exchanger 12 is provided in the outdoor unit, and is connected to the outlet of the compressor 11 so that the refrigerant can flow, thereby condensing the refrigerant introduced from the compressor 11 to inject a high temperature refrigerant.

The outdoor fan 13 is provided on one side of the outdoor heat exchanger 12 and promotes heat dissipation of the refrigerant by rotation. At this time, the outdoor fan is set to the rotational speed according to the temperature of the outdoor heat exchanger outlet detected at the start time of operating in the refrigerant amount detection mode, and rotates until the refrigerant amount detection mode ends at the set rotational speed.

The accumulator 14 is installed in the suction pipe of the compressor 11 to separate the liquid refrigerant from the refrigerant flowing into the compressor.

Among the plurality of temperature sensing units, the first temperature sensing unit T1 is provided at the outlet of the outdoor heat exchanger 12 to sense the temperature of the outlet of the outdoor heat exchanger 12 and transmits the sensed temperature to the controller.

The plurality of indoor heat exchangers 15 are disposed in the respective indoor spaces and inject the low temperature refrigerant by evaporating the refrigerant flowing from the outdoor heat exchanger 12.

The second temperature detecting unit T2 is provided at each inlet of each of the plurality of indoor heat exchangers 15 to sense the temperature of the inlet of each indoor heat exchanger 15 and transmits the detected temperature to the controller.

The third temperature detecting unit T3 is provided at the outlet of each of the plurality of indoor heat exchangers 15 to sense the temperature of the outlet of each indoor heat exchanger 15 and transmits the detected temperature to the controller.

The main solenoid expansion valve 16 is provided at the outlet side of the outdoor heat exchanger, and a branch flow path is formed at the outlet side of the main solenoid expansion valve along the flow direction of the refrigerant so that refrigerant can branch into each of the plurality of indoor heat exchangers. At the inlet side of the indoor heat exchanger of each branch flow passage, an indoor electromagnetic expansion valve 17 is provided to expand and expand the refrigerant under reduced pressure.

The controller 19 controls the compressor provided in the outdoor unit to be driven for a predetermined time of about 20 seconds at a predetermined operation rate in order to keep the refrigerant amount circulated in the refrigerant amount detection mode.

At this time, it is controlled to drive at a predetermined ratio of the total operation rate of the plurality of compressors or to drive only one of the plurality of compressors at an operation rate of 100%.

The control unit 19 is detected by the first temperature sensing unit T1 at the start of operation in the refrigerant amount detection mode in order to maintain the pressure of the discharge port (ie, the high pressure side) of the compressor 11 within a predetermined range. The rotational speed of the outdoor fan 13 is set based on the initial outlet temperature of the outdoor heat exchanger and controlled to rotate constantly until the refrigerant amount detection mode ends at the set rotational speed.

At this time, the higher the initial outlet temperature of the outdoor heat exchanger, the faster the rotation speed of the outdoor fan.

In order to prevent the operation of the plurality of indoor units from being stopped, the controller 19 sets the target temperature of the indoor heat exchanger provided in each of the plurality of indoor units to a minimum of about 3 ° C., and then controls all indoor units to operate in the cooling mode.

At this time, the indoor unit is forced to set the target temperature to 3 ℃, even if the indoor air temperature is lowered below the general minimum cooling control temperature of 18 ℃, the indoor unit is operated without turning off, and the compressor also operates without being turned off for a predetermined time.

The controller 19 calculates a difference between the inlet and outlet temperatures of each indoor heat exchanger detected through the second and third temperature sensing units T2 and T3, and calculates the degree of superheat at each outlet of the indoor heat exchanger. The opening degree of each indoor electromagnetic expansion valve 17 is controlled so that superheat degree may become a fixed temperature of about 3 degreeC. In addition, if the indoor temperature is lowered while the indoor unit is continuously operated in the cooling mode, the pressure of the compressor inlet is lowered, thereby controlling the indoor electromagnetic expansion valve.

At this time, when the degree of superheat at the outlet of the indoor heat exchanger decreases, the refrigerant becomes saturated and the changed liquid refrigerant accumulates in the accumulator.

Accordingly, since the accuracy of the refrigerant amount detection is lowered, the indoor electromagnetic expansion valve is controlled so that the superheat degree at the outlet of the indoor heat exchanger is about 3 ° C so that the gaseous refrigerant is sent to the accumulator.

That is, by giving the superheat degree of refrigerant gas sucked into the compressor a little, it reduces the power required when the compressor compresses, and also prevents the liquid compression of the compressor.

The control unit 19 calculates the supercooling degree of the outdoor heat exchanger outlet by comparing the difference between the saturation temperature corresponding to the pressure sensed at the compressor outlet through the second pressure sensing unit PH and the temperature detected at the outlet of the outdoor heat exchanger. do.

The controller 19 detects the refrigerant amount according to the high pressure detected by the compressor discharge port, the low pressure detected by the compressor suction port, and the supercooling degree of the outdoor heat exchanger outlet, and then determines whether the refrigerant leaks according to the detected refrigerant amount.

At this time, the pressure at the compressor discharge port and the pressure at the outlet side of the outdoor heat exchanger are small even though there is a pressure drop, and thus the saturation temperature is calculated by using the pressure at the compressor discharge port when the supercooling degree is calculated.

In addition, the controller controls the valves connected to various bypass pipes, such as a hot gas valve, a liquid valve, a vent valve, and a supercooled heat exchanger bypass valve, to be closed when the outdoor unit is operated in the refrigerant amount detection mode. .

2 is a configuration diagram of a multi air conditioner according to another embodiment, and includes a plurality of outdoor units 1, a plurality of indoor units 2 connected to each outdoor unit, and a central controller 3 connected to a plurality of outdoor units. .

Each outdoor unit 1 includes a compressor 11, an outdoor heat exchanger 12, an outdoor fan 13, an accumulator 14, a main electromagnetic expansion valve 16, a first temperature sensing unit T1, and first and second units. Composed of pressure sensing units PH and PL, a plurality of indoor units 2 connected to each outdoor unit are arranged in parallel, and each indoor unit 2 includes an indoor heat exchanger 15, an indoor electromagnetic expansion valve 17, and a second unit. And three temperature sensing units T2 and T3. Here, the technical features of each component are the same as in the embodiment to be omitted.

Each outdoor unit further includes an input unit 18 to receive the operation mode of the air conditioner through the input unit. In particular, when the operation mode signal of the refrigerant amount detection mode is input from the user, the input operation mode signal is transmitted to the controller 19.

As described in one embodiment, if each refrigerant amount of the plurality of outdoor units is detected according to the control driving of each component unit after performing the control command of the outdoor unit controller 19, the controller 19 of each outdoor unit stores the detected amount of refrigerant in wired / wireless communication. Control to transmit to the central control unit 3 connected to.

When the refrigerant amount detection mode signal is transmitted from the plurality of outdoor units, the central controller 3 checks the stable state for a predetermined time and stores the amount of refrigerant transmitted from the plurality of outdoor units, respectively, and applies the error according to the model of each outdoor unit. The average refrigerant amount of the outdoor unit is calculated.

The central controller 3 determines whether the refrigerant leaks according to the calculated average amount of refrigerant, and displays the amount of refrigerant and whether the refrigerant leaks through an application programmed in the central controller.

3 is a flowchart illustrating a refrigerant amount detection method of a multi-air conditioner according to an embodiment, which will be described with reference to FIG. 1.

When the refrigerant amount detection mode is selected through the input unit 18 of the outdoor unit 1, the compressor 11 of any of the plurality of compressors is fixed at a constant operation rate in order to keep the refrigerant amount circulated in the refrigerant amount detection mode. Drive for time (102).

In order to maintain the pressure of the discharge port of the compressor 11 within a predetermined range, the outdoor unit is based on the first outlet temperature of the outdoor heat exchanger detected by the first temperature detector T1 at the start of operation in the refrigerant amount detection mode. The rotation speed of the fan 13 is set and rotated constantly at the set rotation speed (103).

At this time, the rotation speed corresponding to the outlet temperature of the outdoor heat exchanger is set in advance, and the higher the outlet temperature, the faster the rotation speed of the outdoor fan.

In addition, the valves connected to various bypass pipes, such as hot gas valves, liquid valves, and vent valves, which are bypassed from the outdoor unit, are closed.

In order to prevent the operation of the plurality of indoor units from being stopped, the target temperature of each of the indoor heat exchangers 15 provided in each of the plurality of indoor units is lowered to a minimum of about 3 ° C., and then all the indoor units are operated in the cooling mode (104).

At this time, the indoor unit is forced to a target temperature of 3 ℃, even if the indoor air temperature is lowered below the general minimum cooling control temperature of 18 ℃, the indoor unit and the compressor does not turn off and operate for a predetermined time.

When the degree of superheat at the outlet of the indoor heat exchanger is lowered, the refrigerant becomes saturated and the changed liquid refrigerant accumulates in the accumulator. Therefore, each room detected by the second and third temperature sensing units T2 and T3 is accumulated. By calculating the difference between the inlet and outlet temperatures of the heat exchanger 15, the superheat degree of each indoor heat exchanger outlet is calculated (105), and each indoor electromagnetic expansion valve so that the calculated superheat is a constant temperature of about 3 ° C. The opening degree control of the control unit 17 is controlled 106.

That is, by controlling the indoor expansion valve 17 so that the superheat degree at the outlet of the indoor heat exchanger is about 3 ° C., the superheat degree of the refrigerant gas sucked into the compressor 11 is given to reduce the power required when the compressor is compressed. Effect and also prevents the liquid compression of the compressor.

Next, the supercooling degree of the outdoor heat exchanger outlet is calculated by comparing the difference between the saturation temperature corresponding to the pressure detected at the compressor outlet through the second pressure sensing unit PH and the temperature detected at the outlet of the outdoor heat exchanger (S107). .

Next, the amount of refrigerant is detected according to the pressure of the compressor suction port sensed by the first pressure detector PL, the pressure of the compressor discharge port detected by the second pressure detector PH, and the supercooling degree of the outlet of the outdoor heat exchanger. 108, it is determined whether the refrigerant leaks according to the detected amount of refrigerant (109).

At this time, the pressure at the compressor discharge port and the pressure at the outlet side of the outdoor heat exchanger are small even though there is a pressure drop, and thus the saturation temperature is calculated by using the pressure at the compressor discharge port when the supercooling degree is calculated.

4A and 4B are flowcharts illustrating a refrigerant amount detection method of a multi-air conditioner according to another embodiment, which will be described with reference to FIG. 2.

When the refrigerant amount detection mode is selected 201 through the input unit 18 of each outdoor unit 1, in order to keep the refrigerant amount circulated in the refrigerant amount detection mode, one of the compressors 11 of the plurality of compressors may be operated at a constant operation rate. It is driven for a predetermined time (202).

In order to maintain the pressure of the discharge port of the compressor 11 within a predetermined range, the outdoor unit is based on the first outlet temperature of the outdoor heat exchanger detected by the first temperature detector T1 at the start of operation in the refrigerant amount detection mode. The rotation speed of the fan 13 is set and rotated constantly at the set rotation speed (203).

In addition, the valves connected to various bypass pipes, such as hot gas valves, liquid valves, and vent valves, which are bypassed from each outdoor unit, are closed.

In order to prevent operation of the plurality of indoor units, the target temperature of the indoor heat exchanger 15 provided in each of the plurality of indoor units is lowered to the minimum and set to about 3 ° C., and then all the indoor units are operated in the cooling mode (204).

Even if the indoor unit is forced to the target temperature of 3 ° C and the indoor air temperature drops below 18 ° C, which is the general minimum cooling control temperature, the indoor unit and the compressor do not turn off and operate for a predetermined time.

When the degree of superheat at the outlet of the indoor heat exchanger is lowered, the refrigerant becomes saturated and the changed liquid refrigerant accumulates in the accumulator. Therefore, each room detected by the second and third temperature sensing units T2 and T3 is accumulated. By calculating the difference between the inlet and outlet temperatures of the heat exchanger 15, the superheat degree of each indoor heat exchanger outlet is calculated (205), and each indoor solenoid expansion valve so that the calculated superheat is a constant temperature of about 3 ° C. The opening degree control of 17) is controlled (206).

Next, the supercooling degree of the outdoor heat exchanger outlet is calculated by comparing the difference between the saturation temperature corresponding to the pressure sensed at the compressor outlet through the second pressure sensing unit PH and the temperature detected at the outlet of the outdoor heat exchanger (207). .

Next, the amount of refrigerant is detected according to the pressure of the compressor suction port detected through the first pressure sensing unit PL, the pressure of the compressor discharge port detected through the second pressure sensing unit PH, and the supercooling degree of the outlet of the outdoor heat exchanger. (208).

Next, each outdoor unit and each component of the outdoor unit detects each refrigerant amount of the plurality of outdoor units by performing a control command of the corresponding outdoor unit controller 19, and the control unit 19 of each outdoor unit stores the detected refrigerant amount in a central control unit (wired or wireless communication). 3) (209).

Next, when the refrigerant amount detection mode signal is transmitted from the plurality of outdoor units, the central controller 3 checks the stable state for a predetermined time of about 10 minutes (210), and after a predetermined time, the temperature change at the compressor outlet is about ± It is determined whether the predetermined range of 3 ℃ (211).

When the temperature change at the next compressor outlet is within a certain range, the number of outdoor units in which the amount of refrigerant is transmitted is determined (212).

In this case, when the refrigerant amount is transmitted from at least two outdoor units, an error according to the model of each outdoor unit is applied (213) to calculate the average amount of refrigerant of the plurality of outdoor units and display the calculated amount of refrigerant in the application of the central controller (214).

If the amount of refrigerant is transmitted from one outdoor unit, an error according to the model of the outdoor unit is applied (215) to calculate the amount of refrigerant, and the calculated amount of refrigerant is displayed on the application of the central controller (216).

Next, the central controller 3 determines whether the refrigerant leaks according to the calculated average amount of refrigerant 217, and displays whether the refrigerant leaks through an application programmed in the central controller.

1 is a block diagram of a multi air conditioner according to an embodiment of the present invention.

2 is a block diagram of a multi air conditioner according to another embodiment of the present invention.

3 is a flowchart illustrating a control method of a multi air conditioner according to an embodiment of the present invention.

4A and 4B are flowcharts illustrating a control method of a multi air conditioner according to another embodiment of the present invention.

Description of the Related Art [0002]

1: outdoor unit 2: indoor unit

11: compressor 12: outdoor heat exchanger

13: outdoor unit fan 14: accumulator

15: indoor heat exchanger 16: main expansion valve

17: indoor expansion valve 18: input

19: control unit

Claims (11)

Outdoor unit; A compressor provided to the outdoor unit; At least one indoor unit connected to the outdoor unit; The compressor is provided in the outdoor unit and drives the compressor at a constant operation rate. Even though the control temperature of the at least one indoor unit is lower than a target temperature, the compressor is driven for a predetermined time and the amount of refrigerant circulated for the predetermined time is detected. And a controller configured to determine whether the refrigerant is leaked according to the detected amount of refrigerant. The method of claim 1, Further comprising: a first pressure sensing unit for detecting the inlet pressure of the compressor, a second pressure sensing unit for detecting the outlet pressure, a first temperature sensing unit for sensing the heat exchanger outlet temperature of the outdoor unit; The control unit calculates a supercooling degree according to a difference between a saturation temperature corresponding to the compressor outlet pressure and a heat exchanger outlet temperature of the outdoor unit, and detects a refrigerant amount through the supercooling degree and the inlet and outlet pressures of the compressor. . The method of claim 2, wherein the control unit And a plurality of air conditioners for rotating the outdoor unit fan at a rotational speed corresponding to a temperature initially sensed by the first temperature sensing unit at a time when the compressor starts to operate at a constant operation rate so that the discharge pressure of the compressor is kept constant. delete The method of claim 1, Further comprising a second temperature sensing unit for detecting the inlet temperature of the heat exchanger of the at least one indoor unit and a third temperature sensing unit for detecting the outlet temperature, The control unit controls the opening degree of the indoor electromagnetic expansion valve provided in the indoor unit to calculate the superheat degree according to the temperature difference between the inlet temperature and the outlet temperature of the heat exchanger of the at least one indoor unit and to maintain the calculated superheat degree at a constant temperature. Multi air conditioner. The method of claim 1, And a plurality of outdoor units, the air conditioner further comprising a central control unit for determining whether the refrigerant is leaked according to the amount of refrigerant transmitted from the control unit provided to each of the plurality of outdoor units. When the refrigerant amount detection mode is selected, the compressor is driven at a constant operation rate. Sensing the temperature of the outdoor heat exchanger outlet provided in the outdoor unit; Setting the rotation speed of the outdoor fan provided in the outdoor unit based on the temperature of the outdoor heat exchanger outlet first detected at the start of operation of the refrigerant amount detecting mode; Control the rotation speed of the outdoor fan to the set rotation speed, Detect the amount of refrigerant, The control method of the air conditioner for determining whether the refrigerant leaks in accordance with the detected amount of refrigerant. The method of claim 7, wherein the driving of the compressor at a constant operating rate, And controlling the operation of the compressor for a predetermined time even if the control temperature of the at least one indoor unit connected to the outdoor unit is lower than a target temperature. The method of claim 7, wherein detecting the amount of refrigerant, Detecting the pressure of the inlet and outlet of the compressor; Calculating the supercooling degree according to the difference between the saturation temperature according to the discharge pressure of the compressor and the initial sensing temperature of the outdoor heat exchanger outlet of the outdoor unit, And controlling the amount of refrigerant through the subcooling and pressures of the inlet and outlet of the compressor. The method of claim 7, wherein detecting the amount of refrigerant, After detecting the inlet and outlet temperature of the indoor heat exchanger provided in at least one indoor unit connected to the outdoor unit calculates the degree of superheat according to the temperature difference between the inlet and the outlet, And controlling the opening degree of the indoor electromagnetic expansion valve provided in the indoor unit such that the superheat is maintained at a constant temperature. The method of claim 7, wherein If the outdoor unit is a plurality, the control method of the multi-air conditioner to calculate the average refrigerant amount of the detected refrigerant amount of the plurality of outdoor units and to determine whether the refrigerant leaks in accordance with the average refrigerant amount.

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